Change in Mechanical Properties and Microstructure of ARB Processed Ti during Annealing
Change in Mechanical Properties and Microstructure of ARB Processed Ti during Annealing
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DOI：
10.2320/matertrans.me200710
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发表时间：
2008
影响因子：
1.2
通讯作者：
D. Terada;M. Inoue;H. Kitahara;N. Tsuji
中科院分区：
文献类型：
--
作者：
D. Terada;M. Inoue;H. Kitahara;N. Tsuji
采用累积叠轧工艺在室温下制备了6次循环的超细晶工业纯钛。显微组织由平均晶粒尺寸为90 nm的等轴晶粒组织和平均片层间距为70 nm的片层边界组织组成。经过6个循环处理的试样ARB随后在不同温度下退火1.8 ks。在400 ℃退火后，ARB试样显示出由晶粒尺寸约为0.5 mm的再结晶晶粒组成的部分再结晶组织和恢复的超细组织。在500 ℃退火后，显微组织中充满了平均晶粒尺寸约为2 mm的等轴再结晶晶粒。通过拉伸试验研究了ARB处理和随后退火试样的力学性能。随着退火温度的升高，合金的抗拉强度不断降低，而总延伸率不断增加。结果发现，拉伸强度线性下降，增加总伸长率的强度-塑性平衡图，这是显着不同的情况下，铝和无间隙原子（IF）钢的强度-伸长率的平衡表现出权衡关系。结果表明，超细晶Ti比Al和IF钢具有更好的强韧性平衡。[doi：10.2320/matertrans.ME200710]
Ultrafine grained commercial purity titanium (CP-Ti) was fabricated by accumulative roll-bonding (ARB) process up to 6 cycles at ambient temperature. The microstructure was composed of the equiaxed grain structure having a mean grain size of 90 nm and the lamellar boundary structure having a mean lamellar spacing of 70 nm. The specimen ARB processed by 6 cycles were subsequently annealed at various temperatures for 1.8 ks. After annealing at 400 � C, the ARB specimen showed the partially recrystallized microstructure composed of recrystallized grains with grain size of approximately 0.5 mm and the recovered ultrafine structure. After annealing at 500 � C, the microstructure was filled with the equiaxed recrystallized grains having a mean grain size of approximately 2 mm. The mechanical properties of the ARB processed and subsequently annealed specimens were investigated by tensile test. The tensile strength decreased and the total elongation increased continuously with increasing the annealing temperature. It was found that the tensile strength decreased linearly with increasing the total elongation in a strength-ductility balance plot, which was significantly different from the cases of Al and the interstitial free (IF) steel where the strength-elongation balance showed a trade-off relationship. The result indicates that ultrafine grained Ti has an excellent strength-ductility balance compared with Al and IF steel. [doi:10.2320/matertrans.ME200710]